Sheryl Sandberg on the moment she found her husband dead.

It’s been a year since she lost her beloved husband in a freak tragedy.

Yet, it is only now that Facebook COO, Sheryl Sandberg has spoken publicly about the effect her husband’s death has had on her life.

“I’ve not spoken publicly about this before and it’s hard. For many months I was swallowed in the deep fog of grief, an emptiness that fills your heart and your lungs, constricts your ability to think, or even to breathe,” Sandberg told a University of California, Berkeley graduation class of 4,700 seniors in a Facebook live video.

"I'm sharing this with you today in the hopes that on this day in your lives, with all the momentum and the joy, you can learn in life the lessons I only learned in death. Lessons about hope, about strength and about the light within us that will not be extinguished."

Sandberg's husband David Goldberg, CEO of SurveyMonkey, was 47 when he passed away last May.

He suffered a brain injury during exercise while he was on holidays with his family.

"His death was sudden and unexpected," Sandberg said.

"We were at a friend’s fiftieth birthday party in Mexico. I took a nap. Dave went to work out. What followed was the unthinkable—walking into a gym to find him lying on the floor. Flying home to tell my children that their father was gone. Watching his casket being lowered into the ground."

Sandberg told the graduating class she had learned a lot of things since her husband's death.

"Dave's death changed me in very profound ways," Sandberg said.

"I learned about the depths of sadness and the brutality of loss. But I also learned that when life sucks you under, you can kick against the bottom, break the surface and breathe again. I learned that in the face of the void - or in the face of any challenge - you can choose joy and meaning."

This is the first time Sandberg has spoken publicly about her husband's death, yet she has written a number of posts on her Facebook page over the past year, thanking the public for their unwavering support.

One such post was written on Mother's Day, where Sandberg wrote about raising children on her own.

"For me, this is still a new and unfamiliar world. Before, I did not quite get it. I did not really get how hard it is to succeed at work when you are overwhelmed at home," Sandberg wrote in her ode to single mothers.

"I did not understand how often I would look at my son’s or daughter’s crying face and not know how to stop the tears. How often situations would come up that Dave and I had never talked about and that I did not know how to handle on my own. What would Dave do if he were here?"

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